Gravity Well Of A DarkStar

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ooheadsoo

Gravity Well Of A DarkStar
« Reply #40 on: 29 May 2005, 12:56 am »
This is just what I was thinking about.  If it can image with nice depth...Geez, might be a nice fun project.  Only problem would be flush mounting the driver.

tianguis

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Gravity Well Of A DarkStar
« Reply #41 on: 29 May 2005, 01:12 am »
Dan, JLM:
        Thanks for your inputs.
        Actually, what I was envisioning was a corner cab open only at the bottom. I haven't run any numbers, but (depending on one's ceiling height) it seems that there's potential for better bass and control of the rising FR without using digital correction. Gotta haul out the Behringer again.  :mrgreen:

Larry

Dmason

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Gravity Well Of A DarkStar
« Reply #42 on: 29 May 2005, 01:37 am »
Larry

that would work, but the baffle would have to be tied to the ceiling. Either way. I prefer the idea of a ceiling vent. Bigger sound potentially.

Terry Cain's "Bigger Is Better" TQWT apparently sounds pretty damn big, using only the Fostex 168Sig. Imagine one with the Visaton :o  Terry strongly advocated the BIB concept for the higher Q drivers, to me. If the 168 Sig works @ 26,  ....   .7??  I have run some numbers this afternoon, preliminary results look promising. Very off my own topic I realize, but only passive components are illegal here. This would produce bass sound like pro audio, no need for anything like a sub with this outfit. I think it could be modelled to equalize the rising FR of the B200. I prefer an acoustical solution to an acoustical problem. Bigger problem is that I suck at math, so I welcome anyone who wishes to dive into Martin King's MathCAD worksheets, with the TS parameters and correctly do this.

-Richard-

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« Reply #43 on: 29 May 2005, 07:50 am »
Hummmmmm...things are unfolding nicely...

Exciting stuff!!!!!!!

Warm regards -Richard-

JLM

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Gravity Well Of A DarkStar
« Reply #44 on: 29 May 2005, 12:04 pm »
To keep the size of this beast managable and allow for more flexibility, I'd keep the corner baffle separate from the waveguide.  Good to know that someone else thinks the idea to be promising.  Anyone know the angle to cut the waveguide at to provide a flush fit (my 3D geometry is a bit rusty)?

The B200 would predictably be more sensitive/dynamic/present over the F200A.  A more organic sound from the B200 is tempting (due to an unrelated project I just picked up a piece of 34 inch by 48 inch 15/32 inch A/B plywood).

Dmason

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Gravity Well Of A DarkStar
« Reply #45 on: 29 May 2005, 02:57 pm »
JLM

the angle cuts of a waveguide would depend upon the angle of incidence of said guide. Someone with a CAD program could design something which had good lines to it, keeping the ceiling extension not too wide that it might look like some melting chocolate-in-reverse. Done right it could look like two musical instruments in each corner. I imagine there could be good effect coming from an equilateral triangle (45' cuts) mounted into the ceiling corners. I plan on drywalling the back corners of my garage soon, to have .....test corners...

Yes, two other people, with years of experience in dealing with resonant systems in audio think the idea of a powerful wideband system in the corners, a Corner Pipe/OB/IB hybrid would not only work, but would work well, either ceiling or floor load. I still like the idea of a unitized construction, with integral waveguide, although the other way would be a theoretically killer design, a new sonic frontier, and a build requiring two pieces.

People point out the rising FR of the B200 like it is a pox. Not when you are able to digitally contour your sound, --it is just more paint in the pot. People need to know that now we have very cost effective, well designed digital audio manipulation tools, and they are a godsend to home audio, and take the chi chi speaker designer right out of the mix, when it comes to $$$ for speakers...(IMHO) Once you get the hang of the DCX2496, you can make pretty much any speaker combination work. I consider the DEQ as essential for taming and tuning speakers and rooms.

This should be part of the above paragraph.... Adding db, the lower you go, the more it modulates FR higher bandwidth. What the B200 naysayers also do not comment on is the fact that the B200 has VERY healthy output at its Fs. --Try that with the 10X more expensive Lowther PM6A it sounds eerily similar to... In a hybridized open baffle/pipe, this can be harnessed very effectively. Add 97db sensitivity and cost effectiveness, and you might have the new DIY speaker phenom, which sounded pretty phenomenal last night as I listened, with two colleagues who want finished, full range DarkStar systems built and delivered. :o

-Richard-

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Gravity Well Of A DarkStar
« Reply #46 on: 29 May 2005, 06:52 pm »
The linear contrivance of cobbling words together
can go so far in explaining what something looks
like...of course if you already know what it looks like
words can fit that image with some degree of effectiveness...

A picture being worth a thousand words could certainly apply
here...would someone, perhaps JLM or Dan, be kind enough
to point us Pleistocene music lovers to an illustration of what
a wave guide or a Corner Pipe/OB/IB hybrid baffle might actually
look like?

Since I haven't started building my baffles for the soon to arrive
B200's I could implement this idea and comment on its effectiveness...
right now however it is a bit mystifying to me...

Warm regards -Richard-

Dmason

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Gravity Well Of A DarkStar
« Reply #47 on: 29 May 2005, 07:25 pm »
Richard,

There are no pictures, because it is something entirely new.  A WHOLE NEW idea in the realm of speaker design, a little kernel from JLM that we are elaborating on right now. What makes this idea sexy is that it passes muster with two Arch-Lord audio gurus.

Imagine a panel ~16" wide mounted to adjoining corners and the ceiling, extending down to about 20" above the floor, the driver mounted in the panel somewhere around 40" then imagine an equilaterally shaped triangular panel fitting into the floor corner, up, into the enclosure, on about a 60' angle, guiding the backwave onto the floor. It would look reminiscent of a front-firing backhorn. It was also pointed out to me that the B200 works best, open baffle/infinite baffle (Qt=.7 Vas=107L) which makes things potentially, even better. Anyone with CAD should step up to the plate right about now.

The design could be implemented variously between an open baffle with infinite baffle action, and with a calculated CSA could be modelled as a triangular pipe, a mass-loaded transmission line, the triangular shape being optimal in reducing, in fact negating standing waves in the "pipe" such as it is. The driver height would be somewhere about 60" I found a German plan for the only known MLTL for the B200 that has been proven to work. If someone can work the equation to turn CSA from a rectangle to triangle please step up. This could be an insanely easy to build and effective architectural MLTL...We already know that the triangular shaped MLTL for the Jordan JX92S is by far the best sounding out of all of the Jordan designs and according to the builders, the corner loaded Jordan apparently sounds killer. Imagine a Visaton version!!!! This could be a bigger, better, simpler version.

-Richard-

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Gravity Well Of A DarkStar
« Reply #48 on: 29 May 2005, 08:43 pm »
OK Dan...I see what you mean...and patience is in
order to let things evolve with a bit more precision
by the input of AC members with CAD programs who
would be willing to do the math and work things out
a bit more...

I am excited and that makes me a tad impatient to "see"
this thing as "real"...a leap into the physical from the
theoretical...

Nice to be a part of something that is taking shape before our
very eyes...like magic...you have started something very potent
here, Dan, that just wants to keep growing...I suspect we may not
really appreciate its full impact for some time...

Admittedly I am a little slow here to "see" this thing but I am
working on it....thanks for the further illuminations...deeply
appreciate it!!!

Warm regards -Richard- (writing from planet Pleistocene)

JLM

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Gravity Well Of A DarkStar
« Reply #49 on: 30 May 2005, 12:06 pm »
Dan,

Seems like you're floating several ideas here at once and I'm getting confused.

My original concept was simply the 16 inch wide by 72 inch long corner mounted baffle that would be open top and bottom with the driver offset to match seated ear height.  This would provide an effective baffle size of roughly 6 ft by 8 ft, thereby lowering the bass response without EQ.

Assuming that the B200 presentation is "forward" (please confirm) imaging would not suffer with this corner positioning.  If this isn't the case, I'd personally abandon the whole idea.

I didn't want to lose sight of the open baffle/infinite baffle concept (boxless dynamics) and as Vas for the B200 is fairly large the design would need to be more open than closed to fit the concept.

I think the triangular waveguides are a good idea.  My guess is that they wouldn't have to be very big as bass pressure build up in the corners would probably be the biggest real issue here.  They just have to "guide", not become horns.

But I'm less sure about closing one end and designing as a pipe or transmission line.  (I know I mentioned that the original concept looks like a cross between pipe, open baffle, and infinite baffle but I was using the idea of "pipe" in a very generic sense.)  My sense based on your reporting is that it'd be a good idea to retain as much of the open baffle qualities of the design as possible.  This starts to remind me of the Decware HDT speaker design (the most complicated I've found).  It uses twin passive radiators, waveguides, porting, and transmission line loading just to extend bass of a Fostex FE206E to 40 Hz.

This may be a case of taking an idea too far.  Or a design by committee where the original concept gets lost.  Maybe I'm just full of manure.  As Richard says, "Make it as complicated as it needs and be no more."

mcgsxr

Gravity Well Of A DarkStar
« Reply #50 on: 30 May 2005, 01:21 pm »
Just a quick note to affirm that my Visatons have indeed hit the mail (thanks Bob at CSS, and Planet10 on diyaudio), so I will be off to the Home Depot to buy up a sheet of 3/4 inch Russian Birch plywood, and have it carved up to my starting point size of 48 inches by 36 inches.  I would start larger... but my poor Honda Accord cannot swallow anything bigger!  I will report when the drivers show, and the fun begins!

Interesting ideas being floated around here, but for me (perhaps king luddite) they are more complex than I need, to begin with.

Have a good one all,

Dmason

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Gravity Well Of A DarkStar
« Reply #51 on: 30 May 2005, 01:56 pm »
Sorry to have confused you. What I was doing is sewing the seeds of creativity, and seeing what might happen. I may have gotten abit ahead of things because I have been investigating open baffles for this driver for some time now, and only recently discovered the one workable Jumbo MLTL, and it has me interested as well. True, considering Vas, I would think the more open or BIG, the better. There are people who know far, far more than I do about this subject who feel the open corner baffle is not only doable, but a highly effective design, taking advantage of several key aspects of about three different designs.

The B200 is considered to have a "forward" presentation, but that again would depend where someone is sitting, and how it has been implemented, and of course what source and amplification. I am not using forward sounding sources no amplifiers, and I am not an imaging guy, but more about tonal accuracy, as I listen to alot of acoustic instruments playing ensemble. My listening, and aural attenuation to the signature of this driver is through the "lens" of digital EQ, which has been calibrated for the room, for real time considerations, and for channel considerations, relative to where we sit when we are listening. It is simply a very accurate, organic sounding machine, with added depth of field due to the driver's backwave being put in play.

An added element this week will be the addition of Visaton's high sensitivity horn supertweeter to try, although I doubt my ears will hear its addition as essential. The B200 does remarkably well all on its own. I just wanted to check it out and see what it was like. This is a very high sensitivity, short-throw conical horn with AlTi alloy diaphragm and rare Earth SrFeB supermagnet, machined out of a solid billet of stainless, for not alot of dough. It may well become a DarkStar option.

barfind

B200
« Reply #52 on: 31 May 2005, 12:03 pm »
Hello all. I have been useing the B200 for some months now. I drive them with an 8watt SET. I have them in a baffle 600w x 1000h. I have in the same baffle 2x 12" woofers driven by a high current SS amp. Active Xover to  the 12's, but the B200 are running fullrange not thru the xover. Xover point is 180hz.
 This is an amazing speaker. I have never heard anything so dynamic, but still very smooth. Everyone who hears them comments on how smooth they are, but still very fast and dynamic. I have the OB's 1m from the back wall and 350mm from the side walls, slightly tilted and toed in.

Nigel

barfind

B200
« Reply #53 on: 31 May 2005, 12:39 pm »
BTW heres a photo of them. The pioneer drivers have been replaced with QTS 1.46 FS32hz woofers. Much better than the pioneers.

http://www.audiocircle.com/index.php?action=gallery;area=browse;album=577


Nigel

mcgsxr

Gravity Well Of A DarkStar
« Reply #54 on: 31 May 2005, 12:43 pm »
barfind - thanks for sharing your experience - interesting that the 24x48 baffle works so well with the 12 inch subs (I now see that you mean 2 per side!) crossed so high (180Hz).

Could you share the room dimensions too?  Looking to attempt to translate your experience to my proposed ideas.

Oh, and to clarify - you are running the b200's full range (no Xover or impedence compensation, or digital shaping etc) - that is right?  No brightness, or beaminess to the sound for you?

Looking even more forward to getting these babies up and running - off to the Home Depot this AM, to score some 18mm Russian Birch plywood...

GHM

Gravity Well Of A DarkStar
« Reply #55 on: 31 May 2005, 01:00 pm »
Thanks for the pics ..I'm also planning to build some of these speakers also. I can't wait to hear how they sound! :o

Dmason

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Gravity Well Of A DarkStar
« Reply #56 on: 31 May 2005, 02:29 pm »
Thanks Barfind,

Nice looking engine you have.

It is important to note that Barfind does all the tweakage with active XO, and never allows any surgery near the AMP/B200 part of it. This is key. I bet it sounds really fine with a good, low noise single ended tube amp.

Another key tidbit is that in using a trapezoidal baffle, the driver center never sees two of the same radii, which does WONDERS for baffle size : roll off ratio. Wonders, that is. ... Mark, if you sketch out your baffle on graph paper and then figure out the LARGEST trapezoid you can fit within the given perimeter, you are off to a flying start with your shi shi Russian Birch. (and here we thought the best stuff actually came from Ontario)

Today's words are,   router, rebate, threaded-inserts.    If you really want to mount that thing, do all of this. The inserts, the nice chunky 3/8 or 1/2 ones also serve to mass load the driver. And this one needs all the anchorage it can get. That, and the nice stiff, void free ply, and you have a beauty baffle!!!  :mrgreen:

mcgsxr

Gravity Well Of A DarkStar
« Reply #57 on: 31 May 2005, 03:22 pm »
Interesting twist - the trapezoid.  I will have HD cut the square, and then trim one side into an agle to achieve this - tks for the tip.

Quick question about hole size and rebate - I would love to move ahead during the travel time of the drivers... but would hate to be the guy with the wrong size hole when they show... especially the TOO LARGE hole...

From the Net measurements in mm, converting to inches, this appears to be an odd size driver - commonly called an 8 inch, but looks to be more like 8.88...

Any comments/advice/suggestions for exact through hole size?  I am thinking I will wait for the driver to show, and then drill the holes, even though I will be desperate for fast action when that happens!

Dmason

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Gravity Well Of A DarkStar
« Reply #58 on: 31 May 2005, 04:52 pm »
Mark

It's more like a 9 inch driver, its about 8.75" wide. Not small. The Visaton actually has a noble heritage, its size, cone shape and whizzerless wonder seems to be based on the earlier Siemens/Klangfilm drivers of yore. These were designed for high output, long-throw applications in theaters in Europe. In other words, it's not a shrinking violet: it can sink TONS of juice, and loves to be driven. It is a powerful, tough driver with gravitas. It is a dark Star.

Refer to the drawings on the Visaton site. Those ~look like shop drawings for the driver. Always use the actual drivers to mark the drill sites, unless you want to practice your geometry on shi shi plywood.  :nono:  Get some nice phat threaded inserts while at HD. I used SolarRez to anchor them. Easily sanded polyester resin with a photo-catalyst, so no mixing required. Can be found in your local Burlington surf shop.

thayerg

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Gravity Well Of A DarkStar
« Reply #59 on: 31 May 2005, 06:57 pm »
If you want to further stiffen the baffles design the feet so that they incorporate vertical ribs anchored to the back of the baffle. If I understand this correctly they will also increase the apparent acoustic size of the baffle without destroying the wonderful box-free sound of the OB design, provided that the rib depth is not to big. Linkwitz Orions have them.

An alternative to baltic birch is to go to a lumber yard which carries domestic one inch cabinet ply. It's not void free but it's probably more inert anyway. (And not all baltic birch is void free any more anyhow.)

I am sorely tempted to buy a pair of visatons, a sonic impact and a DEQ 2496. I could just about do it if I sold my tube integrated...